Reciprocating internal combustion engines or compressors need to convert the reciprocating motion of the piston to the rotary motion of the crankshaft and vice versa. Wherein, the reciprocating internal combustion engines converts the reciprocating motion of the piston into the rotary motion of the crankshaft, on the other hand, the reciprocating compressor converts the rotary motion of the crankshaft into the reciprocating motion of the piston. Under the current general technology, the conversion process needs a crank linkage mechanism. Due to the presence of link rods in the crank linkage mechanism, the machines are bulky, heavy, and of poor balance performance.
To address these problems, a Chinese patent document CN85100358A discloses a “crank-circular slider reciprocating piston type internal combustion engine”, Chinese patent CN85100359A discloses a “reciprocating piston type compressor with a crank circular slider”. Chinese patent CN1144879A discloses a “crank double circular slider reciprocating piston type internal combustion engine”. Chinese patent document CN1144880A discloses a “crank-multi-circular slider reciprocating piston type internal combustion engine”. The common features of the internal combustion engine lie in a thorough improvement to the crank linkage mechanism of the internal combustion engine under the common technology by using a circular slider with an eccentric hole to replace the link rod. The eccentric circular slider has a cylindrical shape, and has an eccentric round hole parallel to the axis of the circular slider; the eccentric round hole is designed for passing through the crank pin of the crankshaft. The piston of the internal combustion engine comprises crowns at both of its ends and a guiding portion connecting the two crowns, wherein the guiding portion has a round hole thereon. The inner radial surface of the round hole mates with the outer radial surface of the circular slider, the circular slider is placed in the round hole which is on the guiding portion of the piston and cooperates with the outer circumference of the circular slider. When the piston moves reciprocally in the cylinder by the push caused by the combustion gas in the cylinder, the circular slider rotates around its own center, and in turn brings a reverse rotation to the crankshaft, and thus transforms the reciprocating motion of the piston into the rotary motion of the crankshaft, then the power is transmitted outward by the rotating components connected with the crankshaft. The teaching of above mentioned patents can also be applied to the compressors, to obtain a crank circular slider compressor.
In the crank double circular slider reciprocating piston internal combustion engine described in the above mentioned patent document CN1144879A and the “crank multi-circular slider reciprocating piston type internal combustion engine” disclosed in the Chinese patent document CN1144880A, one of the important advantages is that a better dynamic balance can be obtained by reciprocating dynamic balance sliders. However the technical solution using the dynamic balance slider requires that the body provides the dynamic balance slider with a guiding rail so as to realize a reciprocating motion. In many circumstances, the increased guiding rail for reciprocating motion will result in difficultly machining the body and impairing the strength and rigidity of the body so that it is difficult to realize it. And, a sliding friction is caused between the dynamic balance slider and the reciprocating guiding rail so as to reduce the transforming efficiency of power of the whole body.
Especially, utilizing single cylinder engine, the designer mainly take into account the simplicity and light weight of the structure of the single cylinder engine. If a dynamic balance slider is used as a dynamic balance element, a set of reciprocating mechanism needs to be added. In this case, such reciprocating rotary inter-exchangeable mechanism is hard to be named as a single cylinder mechanism and completely abandons the advantage of simplicity and light weight of the single cylinder mechanism.